Brushless DC motors differ from conventional brush-type DC motors in that brushless DC motors are commutated electronically rather than mechanically. A multi-phase brushless DC motor includes a stator and a rotationally mounted rotor. The stator includes a plurality of stator windings that, when controllably energized, generate a rotating magnetic field. The rotor includes one or magnets. Thus, the rotating magnetic field will interact with the rotor, causing the rotor to rotate and generate a torque.
Many brushless DC motors use magnetic sensors, typically Hall sensors, to determine when to controllably energize the stator windings. More specifically, the magnetic sensors sense the rotational position of the rotor and supply the detected rotational position to a controller. The controller, based on the sensed rotor position, controllably energizes the stator windings. Many brushless DC motors also use one or more temperature sensors to sense the temperature of the stator windings. The controller, based on the sensed temperature, may slow the rotation of the rotor or, if the temperature rise is excessive, completely shut the motor down.
Motor manufacturers are continuously looking for ways to reduce component count, overall motor system size, and overall motor system costs. These considerations can present difficulties when end-users want to implement the temperature sensing and control capability. Hence, there is a need for a device that allows for implementation of the temperature sensing and control capability in brushless DC motor control that can reduce component count, and that does not adversely impact overall system size and/or cost. The present invention addresses at least these needs.